Balloon-type catheters and method of manufacture

ABSTRACT

Disposable balloon-type catheters are made from tubes of extruded waterproof plastic having a major lumen and at least one secondary lumen within the tube wall. Such secondary lumens are joined for fluid flow to inflation tubes by a series of cutting and cementing steps and to elastic inflatable balloons which are fitted in special fashion to the distal end of the tube.

United States Patent David S. Sheridan Hook Road, Argyle, N.Y. 12809;Isaac S. Jackson, Greenwich, N.Y. 860,278

Sept. 23, 1969 Dec. 7, 1971 David S. Sheridan Argyle, N.Y.

Inventors Appl. No. Filed Patented Assignee BALLOON-TYPE CATHETERS ANDMETHOD OF MANUFACTURE 9 Claims, 11 Drawing Figs.

US. Cl 156/229, 156/244, 156/257, 156/294, 156/296, 128/349 Int. Cl B32b31/00 Field of Search 156/293,

[56] References Cited UNITED STATES PATENTS 3,528,869 9/1970 Dereniuk156/294 Primary Examiner-Carl D. Quarforth Assistant Examiner-Stephen J.Lechert, r. Attorney-Kemon, Palmer & Estabrook ABSTRACT: Disposableballoon-type catheters are made from tubes of extruded waterproofplastic having a major lumen and at least one secondary lumen within thetube wall. Such secondary lumens are joined for fluid flow to inflationtubes by a series of cutting and cementing steps and to elasticinflatable balloons which are fitted in special fashion to the distalend of the tube.

PATENTED um 1 WI 3525; 793

INVENTORS DAVID S. SHERIDAN ISMC JACKSQN BY [g {FM 4 gshk k ATTORNEYSBALLOON-TYPE CATl-[ETERS AND METHOD OF MANUFACTURE BACKGROUND OF THEINVENTION This invention relates to balloon-type catheters, i.e.,catheters which are provided at the distal end with an inflatableballoon or cuff which serves, during the medical or surgical procedureperformed using the catheter, to retain the catheter in a desiredposition within the patient, to close a passage in the patient, etc.

Medicosurgical tubes may assume a variety of sizes, shapes and beprovided with a variety of fluid openings, couplings, connectors or thelike. Terminology applied to such devices by users, e.g., physicians,surgeons, hospitals, etc., frequently refer to them as catheters, e.g.,rectal catheters, urethral catheters, hemostatic catheters and the like,but in other cases they are referred to as tubes, e.g., endotrachaeltubes, feeding tubes, suction tubes, drain tubes and the like. For thesake of brevity in describing the improved devices of the invention andtheir method of production, the term catheter is employed throughout thespecification and accompanying claims to encompass pertinentmedicosurgical devices whether they be popularly referred to by themedical profession and other users as catheters" or tubes.

The modern trend in medical and surgical practices is toward the use ofdisposable catheters, i.e., those which may be used a single time on onepatient and then discarded. The high cost of labor in sterilizing tubesof the reusable type tends to oflset the cost of a single use disposablecatheter. Also, the use of a disposable catheter reduces cross-infectioncases which constitute a serious problem in hospital operations. Ofcourse, the cost of a disposable catheter must be competitive with thecost of a reusable type over its usable life span plus the cost ofsterilizing the reusable catheter. Hence, it is necessary for theacceptance and a practical utilization of disposable-type catheters thatthey be manufactured at a minimum cost. Reduction in cost of manufactureof simple catheters such as rectal tubes, Foley catheters and the likehave been possible so that reusable catheters of this class are rapidlybeing displaced in the industry by disposable-type catheters. On theother hand, the more complicated construction and manufacturing costsassociated with the production of balloon-type catheters has notpermitted these catheters heretofore to be in major proportion of thedisposable type, i.e., reusable balloon-type catheters are stillextensively used because of cost and construction factors.

A balloon-type catheter normally involves a plurality of lumens onebeing the major lumen which serves to convey urine blood serum, gasesand any other fluid which may be introduced into or removed from thebody of a patient and at least one secondary lumen which is used as aconduit for air or liquid employed in inflating a balloon which forms aportion of the distal end of the catheter. Such secondary lumen isattached to an inflation tube through which the air or liquid used toinflate the catheter balloon is introduced. The manner of attachment ofthe inflation tube to the catheter has been a contributing factor in thecost of manufacture of balloon-type catheters heretofore. The principalmethod of attaining this has been in the past to form the inflation tubeintegrally with the remainder of the catheter by moulding, casting ordipping operations (see U.S. Pat. No. 2,927,584). To attain high ratesof production and low cost of operation, it would be desirable to haveavailable a satisfactory method for producing balloontype catheters byan extrusion method. This necessitates having available some means bywhich the inflation tube may be satisfactorily attached to the extrudedtube forming the major part of the balloon-type catheter. Of course,such an attachment procedure must provide a reliable connection betweenthe inflation tube and the catheter without substantially increasing thecost of manufacture or the rate at which the units may be produced.

Another feature of balloon-type catheters which creates cost andproduction problems in their manufacture is the construction of theinflatable balloon and its method of attachment to the catheter. Thismust be accomplished so that the balloon in the deflated condition willnot present protrusions, edges or the like which prevent the smoothinsertion or withdrawal of the catheter in the patient thereby avoidingdamage to tissues or organs through which the catheter passes during itsuse upon the patient. One method of attachment of the inflation balloonhas involved its inclusion totally inside the wall of the main tubingfonning the catheter (see U.S. Pat. No. 2,919,697). Such construction iscomplicated and involves, however, the problem of an integrally formedinflation tube as discussed above. Other approaches to the problem ofattachment of the inflatable balloon have involved the casting ordipping of a plastic balloon on the end of the catheter (see U.S. Pat.No. 3,292,627) or a concentric arrangement of tubes with grooves cut orotherwise formed in the outside walls of a portion only of the innertube constituting the main body portion of the catheter (see U.S. Pat.No. 2,912,981). While such constructions may be effective in creating anontraumatic balloon attachment to the catheter, the constructionsrequired and the number of steps involved in production of suchcatheters serves to undesirably increase the cost of manufacture.

As previously indicated, the balloon-type catheters encompass a widevariety of specific medicosurgical devices used in different operationsand medical procedures. They may be urethral catheters (see U.S. Pat.No. 2,919,697), endotrachael tubes, hemostatic catheters (see U.S. Pat.No. 3,045,677) or any other of a number of related devices known to themedical art. In addition, such catheters may involve special units ordevices for introducing inflation fluid into the inflatable bag orballoon formed as a part of the distal end of the catheter (see U.S.Pat. Nos. 2,896,629 and 3,409,016). The present invention iscontemplated for use in connection with all forms of balloon-typecatheters.

Another factor that has contributed to the cost of disposable catheters,particularly endotrachael tubes which have a relatively large distal endopening, is the finishing of the distal tip. in the past this hasinvolved extensive hand work, i.e., grinding, buffing and polishing andrequired a high degree of skill in the finishing operators even toaccomplish a mediocre result. The utilization of balloon type as well asother disposable catheters would be improved if a method of finishingthe distal tips with less hard work, need for less skilled workers, orboth, could be provided.

OBJECTS The principal object of the present invention is the provisionof new improvements in catheters and their production. Further objectsinclude the provision of:

I. New methods for the production of disposable plastic balloon-typecatheters. v

2. New forms of extruded plastic catheters having a balloon cufi on thedistal end which has been installed in a manner to give a polished,rounded junction between the balloon shoulders and the outside wall ofthe catheter tube.

3. New methods for affixing inflation tubes to balloon-type catheters"permitting the main body portion of the catheter to be fonned ofextruded waterproof plastic material.

4. Disposable endotrachael tubes having a balloon cuff feature ofimproved design.

5. New methods forv the shaping and polishing of the distal end tip ofmedicosurgical tubes and particularly balloontype catheters comprising amajor lumen and at least one secondary lumen within the wall of thecatheter.

6. Balloon-type catheters of improved design capable of beingmanufactured at low cost and high rates of production to exactspecifications completely competitive on a single use, disposable basiswith reusable tubes of the same general type designed for multiple usewith sterilization between uses.

7. New methods for the formation of arcuate tubing by extrusion having asecondary lumen in the tubing wall on the inside of the tubing are foruse in producing endotrachael tubes.

SUMMARY OF THE INVENTION Theseobjects are accomplished according to thepresent invention by theprovision of balloon-type catheters whichcomprise:

aa anextruded tube formed of flexible waterproof plastic material havinga major lumen with an area equal to at least one-half thecross-sectional area of the tube and at least one secondary lumen ofsmaller diameter than the wall thickness of the tube, all said lumensextending substantially the entire length of the tube,

b. a smoothly rounded distal end on the catheter presenting the majorlumen in full opening and closing the end of said secondary lumen,

c. an inflation tube of flexible waterproof plastic material having anoutside diameter slightly larger than said secondary lumen fixed througha first opening in said tube with the end of the inflation tubeextending into such secondary lumen in the direction of the distal endof the catheter,

d. a second opening cut through the wall of the catheter adjacent thedistal end into communication with said secondary lumen, and

e. an elastic inflatable balloon fixed about the catheter adjacent itsdistal end enveloping said second opening.

In the embodiments of the invention where the catheter has a pluralityof secondary lumens, there will be a separate balloon element andinflation tube for each secondary lumen.

In a preferred embodiment of the invention, the new balloon-typecatheters are endotrachael tubes having an angled distal end tip and apermanent arcuate shape with the secondary lumen being positioned on theinside of the curve of the endotrachael tube. Such endotrachael tubesfurther are preferably formed of plasticized polyvinyl chloridecontaining a small amount of white pigment which gives the tube a milkytranslucency, but retains sufficient transparency to permit the majorlumen of the tube to be viewed through the side walls of the catheter.

The objects of the invention are further accomplished by the method forproduction of balloon-type catheters which comprises:

a. providing an extruded tube of predetermined length formed of flexiblewaterproof plastic material, said tube having a major lumen and at leastone secondary lumen, said major lumen having an area equal to at leastone-half the cross-sectional area of the tube, said secondary lumenbeing of smaller diameter than the wall thickness of the tube, both saidlumens extending the full length of the tube,

b. cutting a first opening through the wall of said tube adjacent thedistal end thereof into communication with said secondary lumen,

c. closing said secondary lumen at the distal end of said tube whileleaving the secondary lumen open for fluid flow proximal of said firstopening,

d. sealing an elastic inflatable balloon to the outside of said tube soas to envelope said first opening,

e. cutting a second opening through the wall of said tube intocommunication with said secondary lumen between said first opening andthe proximal end of the tube, providing a section of extruded tubing ofpredeter mined length having an outside diameter slightly larger thansaid secondary lumen,

g. inserting a heated tapered mandrel into said second opening to causesaid lumen to be expanded in the region of said second opening,

h. removing said mandrel from said second opening, and promptlyinserting one end of said section of extruded tubing into the expandedsecond opening, and

i. allowing said second opening to contract about said inserted end oftubing.

The objects of the invention are further accomplished by forming theballoon cuff on the new balloon-type catheters by a procedure whichcomprises:

a. providing an elastic inflatable balloon having a pair of opposedcircular openings defined by short integral tubular extensions orshoulders, said shoulders having an inside diameter slightly smallerthan the outside diame ter of said extruded tube,

b. fitting said balloon about said tube adjacent one end of the tube bypassing the tube through said shoulders while stretching the shoulderssufficiently to permit such passage,

c. forcing a thin layer of liquid cement between the outside wall ofsaid tube and said tubular extensions with the balloon stationary in thefitted position of said step b, and

d. allowing said cement to harden while the balloon remains in saidfitted position.

The method of closing the secondary lumen distally of the opening whichconnects the secondary lumen to the balloon cuff of the catheter isaccomplished by forcing the distal end of the tube into a mold heated toa temperature sufficient to produce plastic flow of the plastic materialof the tube, the mold having a concave contour to create a smooth convexsurface upon the end of the tube. This heating and molding stepsimultaneously polishes the end of the tubeand closes the secondarylumen so that any fluid passed into the secondary lumen through theinflation tube will be forced to enter the balloon cufl.

Advantageously, the balloon cufi applied to the catheter is made bydipping a mandrel in polyvinyl chloride plastisol to form a balloon cuffwith opposed shouldered openings that are slightly smaller in diameterthan the outside diameter of the catheter, i.e., about 0.5 mm. smallerthan the outside diameter of the catheter tube.

DESCRIPTION OF THE DRAWINGS A more complete understanding of the newmethods and the devices of the invention may be had by reference to theaccompanying drawings in which:

FIG. I is a fragmentary plan view of an endotrachael tube formed inaccordance with the invention showing for most part the distal endportion of the tube and also illustrating the attached balloon inflationmeans of the catheter.

FIG. 2 is an enlarged sectional view taken along the line 2- 2 of FIG.1.

FIG. 3 is a perspective view of an elastic inflatable balloon cuff withopposed shouldered openings of the type used in the invention in formingthe inflatable balloon feature of the new catheters.

FIG. 4 is a a fragmentary perspective view illustrating one step in themethod of affixing a balloon cuff of the type shown in FIG. 3 to thedistal end of a catheter in accordance with the invention.

FIG. 5 is a fragmentary enlarged side view of the section of a catheterin accordance with the invention in one stage of affixing a section ofinflation tube to the secondary lumen of the balloon-type catheter.

FIG. 6 is a fragmentary side view related to FIG. 5 showing the catheterin a further stage of installation of the inflation tube. a

FIG. 7 is a fragmentary side view related to FIGS. 5 and 6 showing theinflation tube installed upon the catheter.

FIG. 8 is an enlarged distal end view of the catheter shown in FIG. Iwith the balloon cuff inflated.

FIG. 9 is a fragmentary side view, partially in section, illustrating astep in the heat molding of the distal end portion of catheters inaccordance with the invention.

FIG. 10 is a fragmentary side view of a catheter in accordance with theinvention which has a pair of inflatable balloons and a pair ofsecondary lumens.

FIG. 11 is an enlarged, sectional view taken on the line 11- ll of FIG.10.

Referring in detail to the drawings, the endotrachael tube 2 comprises anonfibrous tube 4, a distal end 6, a central body portion 8, a proximaland (not shown), inflation means and elastic inflatable balloon means12. As will be understood by those skilled in the art, devices of thistype will vary in size to accommodate different patients and operativeconditions, e.g., a typical endotrachael tube would have an insidediameter of 7.0 mm., an outside diameter of 9.3 mm., a length of about12 inches and will be of arcuate form defining a circle of radius about5-12 inches.

The cross section of the endotrachael tube of FIG. 1 as shown in FIG. 2is representative of all of the balloon-type catheters of the inventionhaving a single secondary lumen. The tube 4 defines a major lumen 14having an area equal to at least one-half the cross-sectional area ofthe tube 4 and a secondary lumen 16 which is of smaller diameter thanthe wall thickness of the tube so that the lumen 16 is formed completelywithin the wall 18 of the tube 4. By this construction, the inside wall20 and outside wall 22 of the tube 4 may be completely smooth anduninterrupted by protrusions, indentations or the like. As aconsequence, the major lumen 14 can have its entire cross sectionmaintained throughout the entire length of the catheter 2 from thedistal end 6 through to the proximal end. Similarly, the outside surface22 of the catheter will present a smooth, uniform circular crosssection.

Using standard extrusion apparatus and techniques, the tube 4 willpresent smooth, highly polished or so-called plate finish" surfaces 20and 22. However, the endotrachael tube 2 or any other balloon-typecatheter formed in accordance with the invention may be provided with afrosted surface, in whole or in part, for the purposes and using themethods described and claimed in copending application, Ser. No.772,890, filed Nov. 4, 1968 for Medicosurgical Tubes Having FrostedSurface."

The inflation means 10 is formed of a section of extruded tubing 24 andclosure means 26. This closure means can take any convenient form suchas a syringe puncture plug of the type shown in U.S. Pat. No. 2,896,629,but in the preferred embodiment shown in FIG. 1, theclosure means 26comprises a cylindrical portion 28, a nipple 30 into which the tubingsection 24 is cemented, a plug 32, a pull-tab 34, and a flexibleconnector strip 36. The entire closure unit 26 is advantageously formedof flexible plastic material by injection molding, but may be formed inany other suitable fashion from other materials such as semirigidplastics, rubber or the like by compression molding, dip coating or thelike.

The balloon means 12 comprises an elastic inflatable balloon cufl" 38having a pair of opposed circular openings 40 and 42 defined by shortintegral tubular extensions or shoulders 44 and 46, respectively. Theshoulders 44 and 46 have an inside diameter slightly smaller than theoutside diameter of the tube 4, e.g., about 0.1 to 1.0 mm. andparticularly about 0.5 mm. smaller than the tube.

The balloon cuff 12 is assembled to the catheter 2 by fitting theballoon cuff over the distal end 6 of the tube by passing the tube 4through the shoulders 44 and 46 while stretching them sufficiently topermit such passage. This positioning of the balloon cufl" about thetube may be helped by dipping the balloon in a lubricant to provideslippage between the balloon shoulders and the outside surface of thetube. Before such placement of the balloon cuff 12 is made, however, asmall hole 48 is cut through the wall of the tube 4 adjacent the distalend 6 so that it is in communication with the secondary lumen 16. Theballoon cuff 12 is then positioned during the fitting step justdescribed so that the balloon 38 envelopes the opening hole 48. In thismanner, any fluid which is forced through the secondary lumen 16 and thehole 48 will enter the inside of the balloon 38.

The balloon means 12 is permanently fixed in the required position byplacing the tube on'a mandrel to straighten the tube and hold it forrotation. Then a hypodermic needle or similar fine diameter hollow tube50 with a right angle tip 52 is positioned as shown in FIG. 4 with theright angle tip 52 under a shoulder of the balloon. A suitable cementsuch as vinyl resin adhesive, is forced from a syringe (not shown) intothe needle 50 and thence between the right angle tip 52 and the balloonshoulder 46. The tube mounted on the mandrel is then rotated while anecessary small amount of liquid cement is forced under the balloonshoulder. The compressive force of the shoulder 46 when handled in thismanner causes a clean smooth joint to be formed between the shoulder 46and the tube 4 and upon drying or hardening of the cement, a permanentconnection between balloon cuff l2 and the tube is obtained. Thisprocedure is repeated for the second shoulder 44 of the balloon cuff. ABead finish 53 can be obtained at the very end junction between theshoulders 44 and 46 and the tube 4 by brushing some of the liquid cementaround the tube at this junction.

The sealing 54 at the distal end 56 of the secondary lumen 16 can beaccomplished, in the manner described hereinafter, prior to theattachment of the balloon to the catheter as just described or at somesuitable subsequent time. Regardless of the particular time forformation of the end sealing 54 of the secondary lumen, this serves toclose off the end of the secondary lumen so that fluid introduced intothe secondary lumen through the inflation means 10 will be required topass through the hole 48 into the space between the balloon 38 and theoutside wall 58 of the tube 4 for the purpose of inflation of theballoon as required in the operative procedure for which the catheter isemployed.

Installation of the inflation means 10 in the catheter is illustrated inFIGS. 5-7. At an appropriate position along the catheter, normallywithin the first half length of the tube from the proximal end, a cut 60is made in the wall of the tubing 4 forming an opening 62 communicatingwith the secondary lumen 16. A small mandrel 64 with a tapered end 66which has been heated to a suitable temperature, e.g., between l50-200F., is forced into the opening 62. As shown in FIG. 6, this produces aconical expansion 68 of the side wall of the tube defining the secondarylumen 16 to occur. A section of tubing 24 having an outside diameterslightly larger than the diameter of the secondary lumen 16 is preparedfor insertion into the expanded hole 62 by applying a thin coating ofsolvent, e.g., dimethyl ketone, to the end 70 of the tubing section 24.The mandrel 64 is then pulled from the expanded opening 68 and the end70 of the tube section is inserted as shown in FIG. 7. Very promptly theelastic memory of the plastic material of which the tube 4 is fonnedwill cause the expanded wall portion 68 to shrink and make a tight jointwith the end 70 of the tube section 24. In the case of endotrachaeltubes made in accordance with the invention, the secondary lumen 16 willbe on the inside of the arcuate shape of the device and,

consequently, the entrance of the inflation tube section 24 into thecatheter tube will also be on the inside curve of the device.

An important feature of catheters produced in accordance with theinvention is illustrated in FIG. 8. The distal end tip 72 is smoothlyrounded in a convex contour. This is important in attaining smooth entryof the catheter into the body of a patient without tendency to tear orinjure tissue during the insertion procedure. Of equal importance,however, is the fact that the smooth rounding of the tube end 72 doesnot result in any reduction in the diameter of the major lumen 14. Thisis in contrast to any prior tube end polishing procedures which haveemployed heat or solvent to attain a polishing of the tube end sincesuch prior known methods result in a contraction of the tube endproducing a substantial reduction in the diameter of the tube opening atthe distal end.

The manner of obtaining the desired smooth rounded finish to the distalend tip 72 without diminution in the lumen 14 and a simultaneous sealingof the end 56 of the secondary lumen 16 is illustrated in FIG. 9. A moldmade of metal or any other suitable material which may be heated to atemperature sufficient to soften the plastic material of which thecatheter is made, e.g., between about l70450 F., is formed with a cavity76 shaped with a rounded bottom 78 to the contour desired in the end 72of the catheter. A central pin or extension 80 having the exact outsidediameter corresponding to the diameter of the major lumen 14 is providedin the mold 74. Also, one or more vent holes 82 are provided in the moldto permit air to escape upon the insertion of the distal end 6 of thecatheter into the heated mold 74. With the mold heated as indicated, thedistal end of the catheter is forced into the mold cavity 76 withsufficient pressure at the temperature of the mold to create plasticflow in the plastic material of the tube 4. This causes the tip 72 ofthe tube to be contoured into a smoothly rounded tip and at the sametime to produce the seal 54 at the end of the secondary lumen 16 for thepurpose described hereinbefore.

The formation of the polished tip on catheters in accordance with theinvention is particularly important with catheters having an angulardistal end, e.g., endotrachael tubes as shown in FIG. 1. Using theprocedures of the invention it is possible to convert a square-cut endof a tube into a polished angular tip in a single pressure moldingoperation. The provision of the small air vent in the base of theshaping mold permits the plastic which is softened by heat exchange withthe heated mold, to flow into the bottom of the mold cavity. In doingthis, a small amount of molten plastic may exit through the vent, butthis can be sheared off easily leaving the catheter with a nicelypolished distal tip. All this is accomplished quickly and withoutreducing the inside diameter or increasing the wall thickness of thecatheter at the distal end.

The embodiment of catheter 84 shown in H68. and 11, comprises twoseparate balloon cuffs 86 and 88. Such double balloon catheters are usedfor example in long-term patients, the separate balloons beingalternately inflated and deflated.

In the catheter 84, the tube 90 has the cuffs 86 and 88 positionedadjacent the proximal end 92 of the catheter which is also provided withan X-ray opaque, slanted tip 94. The balloon 86 is inflatable throughthe secondary lumen 98 while the balloon 88 is inflatable throughthe'secondary lumen 100. The construction of the additional balloon unitwill follow the same procedures described above in connection with thecatheters having a single secondary lumen and will be apparent to thoseskilled in the production of catheters from the descriptions herein.

DISCUSSION OF DETAILS New balloon-type catheters of the invention may bemanufactured to professional specifications and may be produced invarying degrees of flexibility or rigidity by varying the formulation ofthe plastic material from which the tubes are extruded. They may be usedinterchangeably with similar catheters which do not incorporate theimproved features of the new devices of the invention.

The new disposable catheters of the invention should be waterproof,flexible over a relatively wide range of temperatures, resistant toattack by body fluids, capable of being sterilized, such as by exposureto ethylene oxide or gamma radiation, and capable of being produced byextrusion at high speeds and at relatively low costs. There are avariety of plastic materials capable of providing these requirements inthe production of disposable, single use catheters. Advantageously, thenew catheters will be formed of nonfibrous plastic material and aparticularly useful material for this purpose is plasticized polyvinylchloride. However, other thermoplastic materials which are useful informing the catheters are available, e.g., nylon, polyethylene or otherpolyolefins and equivalent materials. A particularly useful material isplasticized polyvinyl chloride formulated to have an extrusiontemperature of about 325375 F. and especially 350 F. The presentinvention is contemplated for use in connection with any plasticmaterial known or found to be useful in the formation of disposablecatheters.

The plastic material used in forming the new catheters may beunpigmented. However, in some cases, pigments designed to give X-rayopacity may be incorporated in the plastic material. In a preferredembodiment of the invention, a small amount of very finely divided whitepigment, e.g., about 0.0] to 1 percent by weight of titanium dioxidepigment, is incorporated in the otherwise transparent plastic materialused in forming the catheter to give the final extruded tube a milkytranslucency, but still retaining sufiicient transparency to permit themajor lumen to be viewed through the sidewall of the catheter. It hasbeen found that this milky translucency creates a clean appearance butretains a see through" quality which emphasizes the presence within themajor lumen of obstruction materials such as articles of body tissue,blood clots and the like.

The new catheters may include special features which are known in theconstruction of medicosurgical tubes and which may be required forparticular procedures in which the new catheters are to be employed.These may include a nonsparking feature (see U.S. Pat. No. 3,070,132),X-ray line feature (see U.S. Pat. No. 2,857,915) or a tapered sectionfeature (see U.S. Pat. No. 2,940,126).

In accordance with known practice, markings may be applied to thecatheters to designate the distance from the distal end to aid thephysician or surgeon in the use of the tube. As will be understood bythose skilled in the art, these distance markings will vary with thetube size, e.g., with a 5.5 mm. l.D. tube, the marks will generallydesignate 12, 13.5 and I5 cm. distance from the distal end and with a7.0 mm., l.D. tube, the markings will designate 18, 20 and 22 cm. fromthe distal end for endotrachael tubes which constitute one of theimportant forms of catheters which can be made by the invention.

FIG. 1 of the drawings shows the new catheter device to have a slantedor sloped end. However, any other form of end or openings as have beenestablished by practice for a particular catheter or which may be foundnecessary hereinafter by new design may be utilized in production ofcatheters in accordance with the invention. This can include catheterswhich have a closed tip and side entering eyes or openings (see U.S.Pat. No. 2,927,584).

Since the new catheters are designed particularly for disposable, singleuse purpose, they are advantageously packaged as single units each inits own individual envelope, tube or other suitable container. A varietyof film or other packaging material is available for this purpose inwhich the catheter may be contained for extended period of time insterile condition immediately available to the physician, nurse or otheruser of the catheter at the location where the catheter will be usedwith the patient. As previously indicated, ethylene oxide, gammaradiation or equivalent methods may be used to sterilize the catheterand the package in the production of such packaged units.

Commercially available extrusion equipment may be used in conjunctionwith suitable extrusion dies to produce the multiple lumen tubingrequired in the creation of balloon-type catheters of the invention.However, in accordance with the invention, a special technique isemployed in producing the multiple lumen tubing for endotrachael tubesof arcuate form with the secondary lumen on the inside of the tubecurvature. When plastic tubing in normally extruded into drums as it iswithdrawn from the extrusion die, it will develop a twist in it. If amultiple lumen tube is produced in such known manner and cut intolengths for making endotrachael tubes, the secondary lumen can, andusually will, be in a twisted or spiralled position. This requires addedsteps for the formation of final catheters, e.g., placement on curvedmandrels, baking and cooling, with properly arranged secondary lumens.

In accordance with the present invention, the multiple lumen tubing asit is extruded, is conveyed away from the extrusion die and directlycoiled onto a drum, being restrained in the conveying to the drum sothat the secondary lumen faces directly toward the drum. The drum is ofa diameter corresponding the radius of curvature desired in the arcuatewhich comprises:

catheter. The tubing is extruded continuously and coiled as indicated onthe drum. As soon as one drum is full, it is replaced with another andthis operation continues until the required amount of tubing isproduced. The drums with the carefully positioned tubing thereon arebaked, e.g., at 150 to 350 F. 10 to minutes and then cooled. When thecooled tubing is removed from the drums, it has the right degree ofcurvature and the secondary lumen is in the right position, i.e., on theinside of the curvature. The tubing is cut in required lengths andformed into catheters as previously described and the final cathetershave the correct curvature and lumen position.

CONCLUSION The invention as described herein provides balloon-type 20The embodiments of the invention in which an exclusive property or rightis claimed are defined in the accompanying claims:

1. Method for the production of balloon-type catheters a. providing anextruded tube of predetermined length formed of flexible waterproofplastic material, said tube comprising a major lumen and a secondarylumen, said major lumen having an area equal to at least one-half thecross-sectional area of the tube, said secondary lumen being of smallerdiameter than the wall thickness of the tube, both said lumens extendingthe full length of the tube,

b. providing an elastic inflatable balloon having a pair of opposedcircular openings defined by short integral tubular extensions of saidballoon, said extensions having an inside diameter slightly smaller thanthe outside diameter of said extruded tube,

c. fitting said balloon about said tube adjacent one end of the tube bypassing the tube through the entire length of 40 said balloon whilestretching said tubular extensions thereof sufficiently to permit suchpassage,

d. with the balloon stationary in the fitted position of said step c,"inserting a fine diameter hollow tube between the outside wall of saidtube and said tubular extensions and forcing liquid cement through saidtube to form a thin layer between said outside wall of the tube and theinside of the tubular extensions, and

e. allowing said cement to harden while the balloon remains in saidfitted position.

2. A method as claimed in claim 1 wherein liquid cement is applied atthe ends of said tubular extensions around the walls of said tube toform beaded joints between the tube and the balloon.

3. Method for the production of balloon-type catheters which comprises:

a. providing an extruded tube of predetermined length formed of flexiblewaterproof plastic material, said tube comprising a major lumen and asecondary lumen, said major lumen having an area equal to at leastone-half the cross-sectional area of the tube, said secondary lumenbeing of smaller diameter than the wall thickness of the tube, both saidlumens extending the full length of the tube,

b. cutting a first opening through the wall of said tube adjacent thedistal end thereof into communication with said secondary lumen,

c. closing said secondary lumen at the distal tip of said tube whileleaving the secondary lumen open for fluid flow proximal of said firstopening,

(1. sealing an elastic inflatable balloon to the outside of said tube soas to envelope said first opening, e. cutting a second opening throughthe wall of said tube into communication with said secondary lumenbetween said first opening and the proximal end of the tube,

f. providing a section of extruded tubing of predetermined length havingan outside diameter larger than said secondary lumen,

g. inserting a heated tapered mandrel into said second opening to causesaid lumen to be expanded in the region of said second opening,

h. removing said mandrel from said second opening, inserting promptlyone end of said section of extruded tubing into the expanded said secondopening, and

i. allowing said second opening to contract about said inserted end oftubing.

4. A method as claimed in claim 3 wherein a layer of liquid cement isapplied to said one end of tubing section before inserting said tubinginto said second opening in step "i."

5. A method as claimed in claim 3 wherein said closing of the secondarylumen in step c is accomplished by forcing the end of the tube into amold heated to a temperature sufficient to produce plastic flow of theplastic material of the tube, said mold having a concave contour tocreate a smooth convex surface upon the tube end in the step of closingof the secondary lumen.

6. A method as claimed in claim 5 wherein the distal tip of said tube iscut at an angle to the longitudinal axis of the tube and said mold iscomplimentarily contoured to create a smoothly rounded tapered distalend tip on the balloon-type catheter.

7. A method as claimed in claim 6 wherein said catheter is anendotrachael tube and the tube provided in step a has a permanentarcuate shape.

8. A method as claimed in claim 6 wherein air within said mold isallowed to escape therefrom through an air bleed hole that extendsthrough a wall of said mold.

9. A method as claimed in claim 4 wherein said tube is made ofplasticized polyvinyl chloride having an extrusion temperature about300-350 F. and said tapered mandrel is heated to a temperature aboutl60200 F.

Disclaimer 3,625,793.Da1)id S. Sheridan, Argyle, and [scum S. Jackson,Greenwich, N .Y.

BALLOON-TYPE CATHETERS AND METHOD OF MANU- FACTURE. Patent dated Dec. 7,1971. Disclaimer filed Apr. 14, 1977, by the assignee, Mallz'nckrodt, I

Hereby enters this disclaimer to claims 1 and 2 of said patent.

[Ofiicz'al Gazette July 26, 1.977.]

2. A method as claimed in claim 1 wherein liquid cement is applied at the ends of said tubular extensions around the walls of said tube to form beaded joints between the tube and the balloon.
 3. Method for the production of balloon-type catheters which comprises: a. providing an extruded tube of predetermined length formed of flexible waterproof plastic material, said tube comprising a major lumen and a secondary lumen, said major lumen having an area equal to at least one-half the cross-sectional area of the tube, said secondary lumen being of smaller diameter than the wall thickness of the tube, both said lumens extending the full length of the tube, b. cutting a first opening through the wall of said tube adjacent the distal end thereof into communication with said secondary lumen, c. closing said secondary lumen at the distal tip of said tube while leaving the secondary lumen open for fluid flow proximal of said first opening, d. sealing an elastic inflatable balloon to the outside of said tube so as to envelope said first opening, e. cutting a second opening through the wall of said tube into communication with said secondary lumen between said first opening and the proximal end of the tube, f. providing a section of extruded tubing of predetermined length having an outside diameter larger than said secondary lumen, g. inserting a heated tapered mandrel into said second opening to cause said lumen to be expanded in the region of said second opening, h. removing said mandrel from said second opening, inserting promptly one end of said section of extruded tubing into the expanded said second opening, and i. allowing said second opening to contract about said inserted end of tubing.
 4. A method as claimed in claim 3 wherein a layer of liquid cement is applied to said one end of tubing section before inserting said tubing into said second opening in step ''''i.''''
 5. A method as claimed in claim 3 wherein said closing of the secondary lumen in step ''''c'''' is accomplished by forcing the end of the tube into a mold heated to a temperature sufficient to produce plastic flow of the plastic material of the tube, said mold having a concave contour to create a smooth convex surface upon the tube end in the step of closing of the secondary lumen.
 6. A method as claimed in claim 5 wherein the distal tip of said tube is cut at an angle to the longitudinal axis of the tube and said mold is complimentarily contoured to create a smoothly rounded tapered distal end tip on the balloon-type catheter.
 7. A method as claimed in claim 6 wherein said catheter is an endotrachael tube and the tube provided in step ''''a'''' has a permanent arcuate shape.
 8. A method as claimed in claim 6 wherein air within said mold is allowed to escape therefrom through an air bleed hole that extends through a wall of said mold.
 9. A method as claimed in claim 4 wherein said tube is made of plasticized polyvinyl chloride having an extrusion temperature about 300*-350* F. and said tapered mandrel is heated to a temperature about 160*-200* F. 